There are 5 US Post Offices in Monroe County serving a total of 8,017 residents equating to 1,603 residents per post office. It's estimated that approximately 12,796 packages are handled across the 5 county post offices annually. Monroe County is located in the Arkansas Delta in the U.S. state of Arkansas. The county is named for James Monroe, the fifth President of the United States. Created as Arkansas's 20th county on November 2, 1829, Monroe County is home to two incorporated town and three incorporated cities, including Clarendon, the county seat, and Brinkley, the most populous city. The county is also the site of numerous unincorporated communities and ghost towns. Occupying only 621 square miles (161,000 ha), Monroe County is the 22nd smallest county in Arkansas. As of the 2010 Census, the county's population is 8,149 people in 4,455 households. Based on population, the county is the fifth-smallest county of the 75 in Arkansas. Located in the Arkansas Delta, the county is largely flat with fertile soils. Historically covered in forest, bayous, swamps, and grasslands, the area was cleared for agriculture by early settlers. It is drained by the Cache River, Bayou DeView, and the White River. Three large protected areas preserve old growth bald cypress forest, sloughs and wildlife habitat in the county: Cache River National Wildlife Refuge (NWR), Dagmar Wildlife Management Area and White River NWR. Interstate 40 is the only Interstate highway in Monroe County, crossing the county from east to west through Brinkley. The county also has three United States highways (U.S. Route 49 [US 49], US 70, and US 79) and twelve Arkansas state highways run in the county. A Union Pacific Railroad line also crosses the county from southwest to northeast."